1 files changed, 72 insertions, 38 deletions
diff --git a/cloudinit/dhclient_hook.py b/cloudinit/dhclient_hook.py
index 7f02d7fa..72b51b6a 100644
--- a/cloudinit/dhclient_hook.py
+++ b/cloudinit/dhclient_hook.py
@@ -1,5 +1,8 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
+"""Run the dhclient hook to record network info."""
+
+import argparse
 import os
 
 from cloudinit import atomic_helper
@@ -8,44 +11,75 @@ from cloudinit import stages
 
 LOG = logging.getLogger(__name__)
 
+NAME = "dhclient-hook"
+UP = "up"
+DOWN = "down"
+EVENTS = (UP, DOWN)
+
+
+def _get_hooks_dir():
+    i = stages.Init()
+    return os.path.join(i.paths.get_runpath(), 'dhclient.hooks')
+
+
+def _filter_env_vals(info):
+    """Given info (os.environ), return a dictionary with
+    lower case keys for each entry starting with DHCP4_ or new_."""
+    new_info = {}
+    for k, v in info.items():
+        if k.startswith("DHCP4_") or k.startswith("new_"):
+            key = (k.replace('DHCP4_', '').replace('new_', '')).lower()
+            new_info[key] = v
+    return new_info
+
+
+def run_hook(interface, event, data_d=None, env=None):
+    if event not in EVENTS:
+        raise ValueError("Unexpected event '%s'. Expected one of: %s" %
+                         (event, EVENTS))
+    if data_d is None:
+        data_d = _get_hooks_dir()
+    if env is None:
+        env = os.environ
+    hook_file = os.path.join(data_d, interface + ".json")
+
+    if event == UP:
+        if not os.path.exists(data_d):
+            os.makedirs(data_d)
+        atomic_helper.write_json(hook_file, _filter_env_vals(env))
+        LOG.debug("Wrote dhclient options in %s", hook_file)
+    elif event == DOWN:
+        if os.path.exists(hook_file):
+            os.remove(hook_file)
+            LOG.debug("Removed dhclient options file %s", hook_file)
+
+
+def get_parser(parser=None):
+    if parser is None:
+        parser = argparse.ArgumentParser(prog=NAME, description=__doc__)
+    parser.add_argument(
+        "event", help='event taken on the interface', choices=EVENTS)
+    parser.add_argument(
+        "interface", help='the network interface being acted upon')
+    # cloud-init main uses 'action'
+    parser.set_defaults(action=(NAME, handle_args))
+    return parser
+
+
+def handle_args(name, args, data_d=None):
+    """Handle the Namespace args.
+    Takes 'name' as passed by cloud-init main. not used here."""
+    return run_hook(interface=args.interface, event=args.event, data_d=data_d)
+
+
+if __name__ == '__main__':
+    import sys
+    parser = get_parser()
+    args = parser.parse_args(args=sys.argv[1:])
+    return_value = handle_args(
+        NAME, args, data_d=os.environ.get('_CI_DHCP_HOOK_DATA_D'))
+    if return_value:
+        sys.exit(return_value)
 
-class LogDhclient(object):
-
-    def __init__(self, cli_args):
-        self.hooks_dir = self._get_hooks_dir()
-        self.net_interface = cli_args.net_interface
-        self.net_action = cli_args.net_action
-        self.hook_file = os.path.join(self.hooks_dir,
-                                      self.net_interface + ".json")
-
-    @staticmethod
-    def _get_hooks_dir():
-        i = stages.Init()
-        return os.path.join(i.paths.get_runpath(), 'dhclient.hooks')
-
-    def check_hooks_dir(self):
-        if not os.path.exists(self.hooks_dir):
-            os.makedirs(self.hooks_dir)
-        else:
-            # If the action is down and the json file exists, we need to
-            # delete the file
-            if self.net_action is 'down' and os.path.exists(self.hook_file):
-                os.remove(self.hook_file)
-
-    @staticmethod
-    def get_vals(info):
-        new_info = {}
-        for k, v in info.items():
-            if k.startswith("DHCP4_") or k.startswith("new_"):
-                key = (k.replace('DHCP4_', '').replace('new_', '')).lower()
-                new_info[key] = v
-        return new_info
-
-    def record(self):
-        envs = os.environ
-        if self.hook_file is None:
-            return
-        atomic_helper.write_json(self.hook_file, self.get_vals(envs))
-        LOG.debug("Wrote dhclient options in %s", self.hook_file)
 
 # vi: ts=4 expandtab